There are seemingly countless forms of divination, which are, for the most part divided into omens (which are the observation of various phenomenon), sortilege (which requires the casting or drawing of something and then the interpreting the results), and augury, which refers specifically to studying bird flight patterns, but can also include a wide range of other testable occurrences.
When you review the range of divination that have been documented through human history, the creativity behind them is quite staggering. Wikipedia lists several hundred. Which gives us a fun exercise: invent your own form of divination, and share it in the comments section here.
Here's mine: Lichomancy (divination with Lichens). Write a question on piece of paper and fold it in thirds. Take the paper and a rock large enough to cover it out to an undisturbed pasture or meadow, where other rocks have lichen. Place the paper under the rock. Wait twenty years. Find the rock and paper, and take it to lichomancer (person who reads lichen), and ask them to interpret the lichen in the context of your original question. Assuming the question is still relevant, and you actually find the stone, you'll have your answer.